Bacterial Vaginosis (BV): This is the most common cause of a fishy-smelling vagina. BV occurs when there is an imbalance in the normal bacterial flora of the vagina, leading to an overgrowth of anaerobic bacteria. The fishy odor is due to the production of amines by these bacteria.

Trichomoniasis: A sexually transmitted infection caused by the parasite Trichomonas vaginalis. It can cause a foul-smelling vaginal discharge, which may be described as fishy.
Vaginal Yeast Infection: Although yeast infections are more commonly associated with a thick, white discharge, some women may experience a fishy odor, especially if the infection is complicated by a secondary bacterial infection.
Poor Hygiene: Infrequent showering or bathing, especially in warm weather, can lead to a buildup of sweat and bacteria in the genital area, resulting in a fishy odor.

Cervical Cancer: Although rare, advanced cervical cancer can cause a foul-smelling vaginal discharge. It is crucial to rule out this diagnosis, especially in women who are not up to date with their cervical cancer screening.
Pelvic Inflammatory Disease (PID): PID is an infection of the female reproductive organs that can cause a range of symptoms, including a foul-smelling discharge. If left untreated, PID can lead to serious complications, such as infertility and chronic pelvic pain.
Foreign Body in the Vagina: A retained foreign body, such as a forgotten tampon, can cause a strong, foul-smelling discharge.

Desquamative Inflammatory Vaginitis (DIV): A rare condition characterized by a severe inflammatory response in the vagina, leading to a foul-smelling discharge.
Vaginal Cancer: A rare type of cancer that can cause a range of symptoms, including a foul-smelling discharge.
Genitourinary Fistula: An abnormal connection between the vagina and another organ, such as the bladder or rectum, can cause a continuous, foul-smelling discharge.